Certified Hemodialysis Technologist/Technician Exam Dialysis Equipment and Troubleshooting 1 — Questions and Answers
Question 1: Which alarm on a hemodialysis machine requires the technician to immediately clamp the blood lines and stop the blood pump?
- Blood leak alarm
- Air detector alarm (Correct answer)
- High venous pressure alarm
- Low arterial pressure alarm
Correct answer: Air detector alarm
An air detector alarm signals air in the venous line, requiring immediate clamping and stopping the blood pump to prevent an air embolism.
Question 2: What does a high transmembrane pressure (TMP) alarm during dialysis typically indicate?
- Clotting in the dialyzer (Correct answer)
- Air in the blood circuit
- Low blood flow rate
- Inadequate dialysate temperature
Correct answer: Clotting in the dialyzer
Elevated TMP often indicates clotting within the dialyzer fibers, increasing resistance to ultrafiltration.
Question 3: A venous pressure alarm that is consistently low may indicate which problem?
- Needle dislodgement from the access (Correct answer)
- Kinked venous blood line
- Clotted venous drip chamber
- High blood flow rate
Correct answer: Needle dislodgement from the access
A consistently low venous pressure can indicate that the venous needle has dislodged from the access, reducing resistance in the return line.
Question 4: What is the purpose of the dialysate bypass system on a hemodialysis machine?
- Increase blood flow rate
- Route dialysate past the dialyzer when an alarm condition is detected (Correct answer)
- Recirculate used dialysate
- Mix concentrate with water
Correct answer: Route dialysate past the dialyzer when an alarm condition is detected
The bypass system diverts dialysate away from the dialyzer when temperature, conductivity, or other alarms occur, protecting the patient from harmful dialysate.
Question 5: Which type of dialyzer membrane is made from synthetic polymer and is generally more biocompatible than cellulosic membranes?
- Cuprophan
- Cellulose acetate
- Polysulfone (Correct answer)
- Regenerated cellulose
Correct answer: Polysulfone
Polysulfone is a high-flux synthetic membrane with superior biocompatibility compared to cellulosic membranes.
Question 6: What does KUF (ultrafiltration coefficient) measure in a dialyzer?
- Clearance of urea per hour
- Volume of fluid removed per hour per mmHg of TMP (Correct answer)
- Blood flow capacity of the dialyzer
- Dialyzer surface area in square meters
Correct answer: Volume of fluid removed per hour per mmHg of TMP
KUF expresses how many milliliters of fluid the dialyzer removes per hour for each mmHg of transmembrane pressure applied.
Certified Hemodialysis Technologist/Technician Exam Dialysis Equipment and Troubleshooting 1
Which alarm on a hemodialysis machine requires the technician to immediately clamp the blood lines and stop the blood pump?